Today I played around with lzma support for tarfile based on your last patch (see issue5689). There are a few minor issues that I just wanted to mention, as they break the tarfile testsuite:
- LZMAFile does not expose a name attribute. BZ2File doesn't either (not in 3.x anyway), but GzipFile does.
- LZMAFile does not allow a 'b' in the mode argument, unlike GzipFile and BZ2File.
- The bz2 module exposes many error conditions as standard Python exceptions, e.g. IOError, EOFError. The lzma module uses LZMAError for all errors without distinction.